Cranking no start diagnosis

[digger]

Car is an 89 e30 bmw m20 6 cylinder has wolf V500 ecu, itb setup, sequential fuel, Bosch waste spark with separate 3 channel Bosch MS ignitor, 60-2 crank as per factory but has cam home signal for sequential runs using alpha-N

Did some work on brake system, didn’t really touch engine other than remove itb intake manifold and a vacuum line to the booster and now car cranks but no start after sitting for only a couple weeks. Recently there have not been any symptoms so no start is totally out of the blue.

Have obviously checked the stuff i messed with and all appears ok and isolated all the changes so I think it is coincidental. No obvious open/broken hoses causing huge vacuum leak or anything

Battery is good and cranks as per usual, did compression test with results as per expected 150-175psi all pots

Is definitely getting fuel as the plugs are wet AF and smell a lot of fuel after multiple no starts so injectors appear to be firing and assume means crank signal and cam signal are atleast functioning. Fuel pump runs and primes ok and rail fuel pressure is as per spec 3b

Logging ECU during a cranking no start event picks up all sensors reading as per normal, appears to get crank signal ~150 to 175rpm which is normal as per other logs from before any issues and the 6 inj outputs and 3 ign outputs are shown as active.

The engine catches occasionally and once almost seemed to run but died so atleast some fuel and spark is occuring

Spark seems perhaps a little weak but is present on all cylinders. Test light on the coil positive is good and is conistent. Incandescent Test light on all 3 coil control wires at the coil plug does not flash/blink suggesting potential control issues thought if it sparks there must be control so possibly a bad test. EDIT: i used a 12V bulb instead of 24V and i can see the flickering due to the switching

Have some spares lying around that are known to be good that i tried, plugs, wires, coil, ignitor/module and no diffence in the slightest.

Any tips for what to check next?

[82eye]

pull a plug to see if it sparks directly. any chance you have a spare coil ?

[digger]

pull a plug to see if it sparks directly. any chance you have a spare coil ?

i have tried a new coil, plugs, ignitor, leads as happened to have these parts already. i confirmed spark at the post of coil, also by removing plug and grounding on body and also using those spark testers with adjustable gap doesnt look like the best spark. There is definelty spark though, but cant be sure its at the right time or strong.

my next plan is to pull plugs and deflood engine add a squirt of oil to add what has been bore washed and to restore compression that is lost when oil is washed away to give it the best chance. Then will double check cam timing and try and see if i can see what the igntion timing being delivered is but not sure how to do that exaclty

[82eye]

i have tried a new coil, plugs, ignitor, leads as happened to have these parts already. i confirmed spark at the post of coil, also by removing plug and grounding on body and also using those spark testers with adjustable gap doesnt look like the best spark. There is definelty spark though, but cant be sure its at the right time or strong.

my next plan is to pull plugs and deflood engine add a squirt of oil to add what has been bore washed and to restore compression that is lost when oil is washed away to give it the best chance. Then will double check cam timing and try and see if i can see what the igntion timing being delivered is but not sure how to do that exaclty

i'm not a lot of help. i think you are on the right track with timing and spark. i'd check the sensors and path from sensor to dme then dme to coil.

[digger]

i'm not a lot of help. i think you are on the right track with timing and spark. i'd check the sensors and path from sensor to dme then dme to coil.

The sensors are all good and signal seen by the DME suggest everything is normal

The dme must be signalling to the ignitor as i could see the flickering showing that the igniter is switching the grounding of the coil negative and there is spark.

Does anyone know if a timing light will be able to show the delivered ignition timing? i know wasted spark with double the firing can mess things up so there is some ones with more functions. i just want see roughly where the spark is firing in relation to TDC

[digger]

so probably important piece of information i recalled recently, i cleaned each throttle by spraying a bunch of carbi cleaner down each throttle / port and may have got too enthusiastic washed the oil away and the engine sat for a couple weeks until i tried to start on sat. Perhaps a bit of light corrosion caused the intiial no start and engine was simply flooded. i did add new plugs and it came close to starting but just needed the cylinder wall to seal a bit better

Anyway cleaned and dried the plugs and let the cylinders breath without the plugs overnight, a squirt of 10W-30 into each plug hole reinstall plugs and it basically started straight up smoked out the neighbours and ran like a champ to operating temp. i havent driven it but cracking the throttle its back to how it was it seems. Need to see if it will restart when cold tommorow. The engine is tired and due for refresh but not had any starting issues until this episode though it does crank a bit longer but has ever since ecu installed back 2007.

Also at cranking the ECU is commanding 8 degrees but im not sure the offset is correct as i dont know whover set it up way back that they used a timing light. The REF in my setup does not match what others ive seen with other ECUs use e.g MS so perhaps the cranking timing is sub optimal to.